Abstract
Background
Posterior cruciate ligament (PCL) injury is common in sports, with anatomical factors like posterior tibial slope (PTS) and femoral intercondylar notch morphology potentially influencing risk. However, evidence remains limited and inconsistent. In addition to the PTS and femoral intercondylar angle, this study also investigated the potential roles of the lateral proximal tibial angle and lateral distal femoral angle in posterior cruciate ligament injuries.
Methods
A retrospective study was conducted including 169 participants: 80 with isolated PCL injuries and 89 controls. Anatomical parameters (PTS, femoral intercondylar angle, etc.) were measured from imaging. Univariate and multivariate analyses were used to evaluate associations with PCL injury.
Results
No significant differences in demographic variables. The PTS was significantly lower in the PCL group (7.81° ± 3.59°) than controls (11.06° ± 4.07°, P < 0.001). The femoral intercondylar angle was also smaller in cases (P < 0.05). Other parameters showed no significant differences. ROC analysis indicated that lower PTS and narrower intercondylar angle were associated with higher PCL injury risk.
Conclusion
PTS ≤ 6.5° and an intercondylar angle ≤ 49.5° were associated with a significantly increased risk of PCL injury.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12891-025-09480-4.
Keywords: Posterior cruciate ligament (PCL), Posterior tibial slope angle, Proximal tibial angle, Distal femoral angle, Intercondylar notch morphology
What is known about this subject
Numerous studies both domestically and internationally have identified a decreased tibial plateau posterior slope and a narrowed femoral intercondylar notch as potential risk factors for cruciate ligament injuries in the knee joint. However, the majority of these investigations have predominantly focused on the anterior cruciate ligament (ACL) of the knee. In contrast, tudies on the association between the proximal tibial angle and distal femoral angle with posterior cruciate ligament (PCL) injury remain scarce. This gap in the literature highlights the need for further exploration into the anatomical and biomechanical factors that may contribute to PCL injuries, as the unique structural and functional characteristics of the PCL warrant a more detailed and specialized analysis.
What this study adds to existing knowledge
Building on the foundation of prior research, the present study has expanded the scope of investigation by incorporating several novel parameters, namely the distal femoral lateral angle, the proximal tibial medial angle, and the intercondylar width of the femur. These additional metrics have been integrated into a comprehensive analysis of their correlation with posterior cruciate ligament (PCL) injury. By quantifying these parameters, we have endeavored to elucidate the relationship between these anatomical features and PCL injury with greater precision. This approach enhances the clarity of the correlation. Furthermore, the findings of this study are expected to offer valuable reference data for clinical practice, potentially aiding in the treatment for PCL injuries.
Introduction
The posterior cruciate ligament (PCL) is a fundamental stabilizer of the knee joint, primarily resisting posterior tibial translation (with a tensile strength exceeding 2000 N) and contributing significantly to rotational stability [1, 2]. Its unique double-bundle structure (anterolateral and posteromedial bundles) enables dynamic tension regulation during knee movement [3–5]. owever, the PCL’s deep location within the joint, enveloped by synovium, often leads to clinically occult injuries and a high misdiagnosis rate (30–40%), especially in complex knee trauma [6–8].
From an epidemiological perspective, PCL injuries account for 3%–20% of sports-related knee injuries [9], and the proportion rises to 38%–44% in cases of traumatic hemarthrosis of the knee [3], ranking second only to anterior cruciate ligament (ACL) injuries [10]. It is noteworthy that isolated PCL injuries represent only 1%–6% [11, 12], while over 60% of cases are associated with concomitant meniscal tears, collateral ligament injuries, or cartilage damage [13]. Combined PCL injuries significantly increase the risk of osteoarthritis (with an incidence rate of 50–80% within 15 years), highlighting the importance of understanding anatomical variations in PCL injuries.
While traditional mechanisms of PCL injury involve high-energy trauma (e.g., dashboard injuries) or sports-related hyperflexion-rotation forces, recent focus has shifted towards anatomical risk factors [14]. Evidence suggests that a decreased posterior tibial slope may elevate PCL injury risk by increasing posterior tibial translation and ligament loading [15, 16]. However, systematic investigation into the role of other parameters, such as the distal femoral angle and proximal tibial angle, and how they modulate PCL tension via intercondylar notch geometry, remains a significant literature gap (Fig. 1).
Fig. 1.
Illustrates the morphological difference of the intercondylar notch. The left panel shows a normal intercondylar notch, while the right panel depicts a stenotic intercondylar notch. Notch stenosis reduces the space available for the cruciate ligaments, thereby increasing the risk of ligament injury
This study aimed to investigate the influence of anatomical parameters, including the PTS, morphology of the femoral intercondylar notch, and the distal femoral and proximal tibial angles, on PCL injuries. We hypothesized that a smaller PTS and a narrower femoral intercondylar angle are independent risk factors for PCL injury.
Materials and methods
General information
This study was a retrospective case-control study conducted at our institution. Approval for this study was obtained from our institutional ethics committee(approval number: 2025-LL-021), which also waived the requirement for informed consent.
This study retrospectively analyzed patients who visited our hospital and underwent knee MRI examinations from January 2021 to December 2024. Patients who met the inclusion and exclusion criteria were divided into two groups: the case group (PCL injury group) and the control group (non-PCL injury group).
Inclusion criteria
Inclusion Criteria for the Case Group: MRI evidence of disruption of PCL continuity or abnormal signal intensity, with arthroscopic confirmation of complete tear; No concurrent complete rupture of other major knee ligaments (Anterior cruciate ligament (ACL), Medial collateral ligament (MCL), Lateral collateral ligament (LCL)).
Inclusion Criteria for the Control Group: MRI and arthroscopic confirmation of no PCL injury; Other knee injuries (e.g., meniscal tears, partial ACL injury) may be present.
Exclusion criteria
Tibial plateau fractures or distal femoral fractures; Previous history of knee surgery or joint replacement; Degenerative osteoarthritis (Kellgren-Lawrence grade ≥ II); Congenital knee deformities or developmental abnormalities; Incomplete or substandard quality of imaging data.
Statistical indicators
Measurement of Anatomical Parameters (Fig. 2): Posterior Tibial Slope Angle (PTSA): Measured on lateral knee radiographs as the angle between the tangent to the tibial plateau and the perpendicular line to the tibial anatomical axis. Proximal Tibial Angle (PTA): Measured on anteroposterior and lateral knee radiographs as the lateral angle between the plane of the tibial plateau and the longitudinal axis of the tibial shaft in the anteroposterior view. Distal Femoral Angle (DFA): Measured on anteroposterior and lateral knee radiographs as the lateral angle between the anatomical axis of the distal femur and the tangent to the femoral condylar joint surface in the anteroposterior view. Intercondylar Notch Morphology: Measured on knee CT scans to determine the intercondylar notch width, intercondylar notch angle (also referred to as the notch angle), intercondylar notch depth, and bicondylar width. The intercondylar notch width index (NWI) was then calculated as the ratio of the intercondylar notch width to the bicondylar width.Confounding Factors: Age; Gender; Body Mass Index (BMI); Mechanism of injury (high-energy/low-energy); Time to treatment: The time interval from injury to hospital admission.
Fig. 2.
a: Distal Femoral Angle (DFA): The lateral angle between the anatomical axis of the distal femur and the tangent to the femoral condylar joint surface in the anteroposterior view of the knee joint; b: Proximal Tibial Angle (PTA): The lateral angle between the tibial plateau plane and the longitudinal axis of the tibia in the anteroposterior view of the knee joint; c: Posterior Tibial Slope Angle (PTSA): The angle measured on the lateral view of the knee joint X-ray between the tangent to the tibial plateau and the vertical line of the tibial anatomical axis, which is calculated as 90° - ∠C; d: Notch Angle: The angle between the medial and lateral walls of the femoral intercondylar notch; e: Notch Depth: The vertical distance from the bottom of the femoral intercondylar notch to the tangent of the distal surfaces of the medial and lateral femoral condyles; Notch Width: The distance between the medial and lateral femoral condyles at the level of half the notch depth, measured perpendicularly to the femoral distal end; f: Bicondylar Width: The horizontal distance between the most lateral points of the medial and lateral femoral condyles at the level of half the notch depth
Data collection and quality control
Radiological measurements were independently performed by one orthopedic surgeon and one senior radiologist using a double-blind method. The Neusoft system (version 5.5) was used with its digital measurement tools. Standardized training was conducted prior to the measurements to ensure consistency in the measurement methods. Each measurement was repeated twice, and the mean value was taken.
Statistical analysis
Statistical analysis was performed using IBM SPSS Statistics Version 27.0. Continuous variables that were normally distributed, including age, BMI, bicondylar width, intercondylar notch width index, intercondylar notch depth, lateral proximal tibial angle, and lateral distal femoral angle, are presented as mean ± standard deviation. Comparisons of these variables between groups were conducted using the independent samples t-test.Continuous variables that were skewed, such as intercondylar notch width and intercondylar angle, are expressed as median (interquartile range, IQR). Group comparisons for these variables were performed using the Mann-Whitney U test.Categorical variables, such as gender and involved side, are described as frequency (percentage). The Chi-square test was employed for comparisons between groups.Multivariate logistic regression analysis was used to identify independent risk factors for PCL injury. The results are reported as adjusted odds ratios (OR) with their corresponding 95% confidence intervals (CI).The cut-off values of anatomical parameters, including the posterior tibial slope and intercondylar angle, were assessed using receiver operating characteristic (ROC) curves, and the area under the curve (AUC) was calculated.The statistical significance level was set at α = 0.05 for all tests, and all tests were two-sided.
Results
Analysis of basic information
A total of 169 subjects were enrolled in this study. The case group, comprising patients with PCL injury, included 80 individuals (48 males and 32 females) and accounted for 47.34%. The control group included 89 individuals (59 males and 30 females) and accounted for 52.66%. There were no significant differences between the two groups in terms of age, gender, BMI, and side of involvement (p > 0.05), indicating comparability (Table 1). In the case group, 20% (16 cases) of the injuries were caused by motor vehicle accidents, 23.75% (19 cases) by sprains, and 56.25% (45 cases) by falls. In the control group, 5.62% (5 cases) of the injuries were caused by motor vehicle accidents, 74.16% (66 cases) by sprains, and 20.22% (18 cases) by falls.
Table 1.
Baseline demographic characteristics of the two groups of participants
| Variable | Total(n = 169) | Control Group (n = 89) | Case Group (n = 80) | Statistic | P |
|---|---|---|---|---|---|
| Age, y | 36.44 ± 12.67 | 36.08 ± 12.63 | 36.85 ± 12.79 | t=−0.39 | 0.694 |
| BMI | 25.14 ± 3.58 | 24.98 ± 3.29 | 25.31 ± 3.89 | t=−0.60 | 0.547 |
| Gender, n (%) | χ²=0.72 | 0.397 | |||
| Male | 107 (63.31) | 59 (66.29) | 48 (60.00) | ||
| Female | 62 (36.69) | 30 (33.71) | 32 (40.00) | ||
| Side, n (%) | χ²=1.38 | 0.239 | |||
| Left | 82 (48.52) | 47 (52.81) | 35 (43.75) | ||
| Right | 87 (51.48) | 42 (47.19) | 45 (56.25) |
Knee anatomical parameters
The mean PTA in the case group was 94.04° ± 2.32°, showing no significant difference compared to the control group (93.48° ± 2.26°; t = −1.57, p = 0.118). Similarly, the DFA did not differ significantly between groups (case group: 80.83° ± 1.97° vs. control group: 81.00° ± 2.10°; p = 0.578). In contrast, the PTSA was significantly lower in the case group (7.81° ± 3.59°) than in the control group (11.06° ± 4.07°; t = 5.46, p < 0.001). Furthermore, three-dimensional CT reconstruction measurements revealed a significantly smaller interquartile range for the intercondylar angle in the case group, with a statistically significant difference between groups (Z = −2.40, P < 0.05). No significant differences were observed in bicondylar width, NWI, intercondylar notch depth, or intercondylar notch width (P > 0.05) (Table 2).
Table 2.
Intergroup analysis of knee anatomical parameters
| Variable | Total | Control Group | Case Group | Statistic | P |
|---|---|---|---|---|---|
| Bicondylar Width, mm | 73.07 ± 5.63 | 73.41 ± 5.38 | 72.68 ± 5.91 | t = 0.84 | 0.401 |
| Intercondylar Notch Width Index (NWI) | 0.26 ± 0.03 | 0.26 ± 0.03 | 0.27 ± 0.03 | t=−0.87 | 0.387 |
| Intercondylar Notch Depth, mm | 28.47 ± 2.82 | 28.54 ± 3.04 | 28.39 ± 2.58 | t = 0.34 | 0.735 |
| Intercondylar Notch Width, mm, M (Q₁, Q₃) | 19.34 (17.27, 21.13) | 19.45 (17.30, 20.84) | 19.27 (17.07, 21.40) | Z=−0.09 | 0.928 |
| Intercondylar Angle,°, M (Q₁, Q₃) | 47.00 (43.00, 53.00) | 47.00 (41.00, 51.00) | 49.50 (44.75, 55.00) | Z=−2.40 | 0.016 |
| Proximal Tibial Angle,° | 93.75 ± 2.30 | 93.48 ± 2.26 | 94.04 ± 2.32 | t=−1.57 | 0.118 |
| Distal Femoral Angle,° | 80.92 ± 2.03 | 81.00 ± 2.10 | 80.83 ± 1.97 | t = 0.56 | 0.578 |
| Posterior Tibial Slope Angle,° | 9.52 ± 4.17 | 11.06 ± 4.07 | 7.81 ± 3.59 | t = 5.46 | < 0.001 |
Univariate and multivariate logistic regression analysis of PCL injury
Univariate logistic regression analysis revealed that a PTSA of ≤ 6.5° (OR = 0.803, 95% CI: 0.733–0.880) and intercondylar angle (°) (OR = 1.050, 95% CI: 1.011–1.091) were independent risk factors for PCL injury (both p < 0.05) (Table 3). Multivariate logistic regression analysis revealed that the femoral angle, tibial plateau posterior slope angle, femoral intercondylar notch width, bicondylar width, intercondylar notch depth, and intercondylar notch angle collectively serve as risk factors for PCL injury (all p < 0.05) (Table 4). ROC curve analysis demonstrated that a PTSA of ≤ 6.5° had predictive value for PCL injury (AUC = 0.734, 95% CI: 0.659–0.809), with a sensitivity of 43.8% and specificity of 92.1% (Fig. 3). An intercondylar angle of ≤ 49.5° also had predictive value for PCL injury (AUC = 0.607, 95% CI: 0.522–0.693), with a sensitivity of 50% and specificity of 69.7% (Fig. 4) (Fig. 5).
Table 3.
Univariate logistic regression analysis of risk factors for PCL injury
| Variables | β | S.E | Z | P | OR (95%CI) |
|---|---|---|---|---|---|
| Age, y | 0.005 | 0.012 | 0.396 | 0.692 | 1.005 (0.981 ~ 1.029) |
| Proximal Tibial Angle,° | 0.107 | 0.069 | 1.559 | 0.119 | 1.113 (0.973 ~ 1.273) |
| Distal Femoral Angle,° | −0.043 | 0.076 | −0.560 | 0.576 | 0.958 (0.825 ~ 1.113) |
| Intercondylar Notch Width, mm | 0.013 | 0.060 | 0.218 | 0.828 | 1.013 (0.901 ~ 1.139) |
| Bicondylar Width, mm | −0.023 | 0.028 | −0.845 | 0.398 | 0.977 (0.926 ~ 1.031) |
| Intercondylar Notch Depth, mm | −0.019 | 0.055 | −0.341 | 0.733 | 0.981 (0.881 ~ 1.093) |
| Intercondylar Angle,° | 0.049 | 0.019 | 2.519 | 0.012 | 1.050 (1.011 ~ 1.091) |
| Posterior Tibial Slope Angle,° | −0.219 | 0.047 | −4.703 | < 0.001 | 0.803 (0.733 ~ 0.880) |
| BMI | 0.026 | 0.043 | 0.605 | 0.545 | 1.027 (0.943 ~ 1.117) |
| Pain Duration, m | −0.016 | 0.014 | −1.123 | 0.261 | 0.984 (0.957 ~ 1.012) |
| Height, cm | −0.032 | 0.019 | −1.710 | 0.087 | 0.968 (0.933 ~ 1.005) |
| Weight, kg | −0.006 | 0.011 | −0.520 | 0.603 | 0.994 (0.974 ~ 1.015) |
OR Odds Ratio, CI Confidence Interval
Table 4.
Multivariate logistic regression analysis of risk factors for PCL injury
| Variables | β | S.E | Z | P | OR (95%CI) |
|---|---|---|---|---|---|
| Intercept | −66.681 | 29.619 | −2.251 | 0.024 | 0.000 (0.000 ~ 0.000) |
| Age, y | 0.017 | 0.017 | 0.990 | 0.322 | 1.017 (0.983 ~ 1.052) |
| Proximal Tibial Angle,° | 0.137 | 0.089 | 1.537 | 0.124 | 1.146 (0.963 ~ 1.365) |
| Distal Femoral Angle,° | 0.301 | 0.121 | 2.493 | 0.013 | 1.351 (1.067 ~ 1.712) |
| Intercondylar Notch Width, mm | −0.386 | 0.147 | −2.627 | 0.009 | 0.680 (0.510 ~ 0.907) |
| Bicondylar Width, mm | −0.164 | 0.068 | −2.418 | 0.016 | 0.849 (0.743 ~ 0.969) |
| Intercondylar Notch Depth, mm | 0.703 | 0.172 | 4.075 | < 0.001 | 2.019 (1.440 ~ 2.831) |
| Intercondylar Angle,° | 0.228 | 0.054 | 4.188 | < 0.001 | 1.256 (1.129 ~ 1.397) |
| Posterior Tibial Slope Angle,° | −0.272 | 0.060 | −4.514 | < 0.001 | 0.762 (0.677 ~ 0.857) |
| BMI | 0.630 | 0.558 | 1.129 | 0.259 | 1.877 (0.629 ~ 5.599) |
| Pain Duration, m | 0.001 | 0.023 | 0.054 | 0.957 | 1.001 (0.957 ~ 1.048) |
| Height, cm | 0.113 | 0.163 | 0.696 | 0.487 | 1.120 (0.814 ~ 1.542) |
| Weight, kg | −0.209 | 0.186 | −1.120 | 0.263 | 0.811 (0.563 ~ 1.169) |
OR Odds Ratio, CI Confidence Interval
Fig. 3.
ROC curve analysis shows that (a) the cut-off value for the intercondylar notch angle was 49.5°, with an AUC of 0.61; and (b) the cut-off value for the posterior tibial slope was 6.5°, with an AUC of 0.73
Fig. 4.
Boxplot showing the distribution of measured variables between the case group and the control group. The posterior tibial slope angle was significantly lower in the case group than in the control group (p < 0.001), and the intercondylar angle was significantly higher in the case group than in the control group (p = 0.012). However, there was no significant difference in the intercondylar notch width index between the two groups (p > 0.05)
Fig. 5.
Panels a, b, c, and d, show that Pearson correlation analysis revealed significant positive correlations of the bicondylar width and intercondylar notch depth with both body weight and height before controlling for confounding factors
Correlation analysis of radiological features
A significant positive correlation was observed between the bicondylar width and body weight (r = 0.55, p < 0.001). The intercondylar notch depth was also significantly positively correlated with body weight (r = 0.34, p < 0.05). Furthermore, the bicondylar width showed a significant positive correlation with height (r = 0.76, p < 0.001), as did the intercondylar notch depth with height (r = 0.47, p < 0.001) (Fig. 4). However, after controlling for the confounding factors of BMI, height, or weight, none of the correlations between these variables remained statistically significant (all p > 0.05).
Discussion
The correlation between posterior tibial slope angle and PCL injury
Currently, the relationship between the PTSA and ACL injury has been extensively studied and is well-established, with a large number of studies confirming that an increased posterior tibial slope angle is a risk factor for ACL injury [16–19]. However, the correlation between the size of the PTSA and PCL injury remains immature, and there is currently no unified quantitative value. Significant controversy still exists. Bernhardson et al. demonstrated in a case-control study that a significantly reduced PTS (5.7 ± 2.1° vs. 8.6 ± 2.2°) is associated with and constitutes a risk factor for PCL injury [15]. Our study also reached the same conclusion. Using a computational model, Shelburne et al. demonstrated that each 1° increase in posterior tibial slope reduces PCL force by 6 N, while a decreased slope increases PCL loading during squatting [20]. Giffin et al. conducted a biomechanical study investigating the effects of posterior tibial slope on PCL-deficient knees and found that increasing the posterior tibial slope helps to reduce posterior tibial translation and restore the stability of the PCL under posterior tibial load and axial compressive load [21]. Similarly, Singerman et al. reported that in total knee arthroplasty with PCL retention, the force on the PCL increases as the posterior tibial slope decreases from 10° to 5°[22]. Biomechanical studies have also shown that a decreased posterior tibial slope is detrimental to the PCL’s ability to maintain posterior stability of the knee joint. In addition, a decreased posterior tibial slope may have an adverse effect on the outcomes of PCL reconstruction and could even be an important risk factor for graft failure [23]. PTS is associated with higher PCL injury risk, consistent with previous studies. This applies to both medial and lateral PTS, though a unified conclusion is lacking. Some studies have demonstrated that an increased LTS/MTS ratio and a decreased MTS are significantly associated with the risk of PCL injury, while LTS is not related to the risk of PCL injury [24]. They suggested that the tibia in patients with PCL injury exhibits net internal rotation [19]. Therefore, the increased LTS/MTS ratio, which leads to net internal rotation of the tibia, may increase the load on the PCL, thereby predisposing it to injury. However, other studies have shown no differences in MTS among different groups [2, 5]. Identifying more risk factors for PCL injury can help patients prevent such injuries early. Compared with MRI, X-ray is less costly and more suitable for screening.
The correlation between femoral intercondylar notch morphology and PCL injury
So far, numerous studies have conducted correlation analyses between the width of the intercondylar notch, bicondylar width, depth of the intercondylar notch, intercondylar angle, and NWI with ACL injury. It has been concluded that a narrow intercondylar notch is a risk factor for ACL injury [25–28]. However, the correlation between these factors and PCL injury has been relatively less studied. Currently, there is a lack of robust research to confirm the relationship, and thus this viewpoint remains worth exploring. Our study found that the width of the intercondylar notch, bicondylar width, depth of the intercondylar notch, and intercondylar notch width index were not significantly correlated with PCL injury. In contrast, a decreased femoral intercondylar angle was significantly associated with an increased risk of PCL injury, whereas previous research on notch morphology has primarily focused on ACL injury. They found that a decreased intercondylar notch width and a decreased intercondylar angle lead to a reduced volume of the intercondylar notch, causing friction and impingement between the ACL and bony structures, thereby resulting in ACL injury [29–32]. A decreased femoral intercondylar angle narrows the intercondylar notch, potentially restricting PCL movement and increasing friction with adjacent structures, thereby raising injury risk. Biomechanically, this angle reduction may alter knee joint load distribution, increasing stress on the PCL and leading to fatigue damage. Further research is needed to clarify the relationship between intercondylar notch morphology and PCL injuries for improved clinical strategies.
The correlation between Proximal Tibial Angle (PTA), and Femoral Distal Angle (FDA) with PCL injury
So far, although many studies have investigated the relationship between knee joint anatomy and ligament injuries, there are still relatively few studies on the correlation between the DFA and the PTA with PCL injury. To our knowledge, this study is the first to conduct a systematic analysis in this area. Our findings revealed that there was no significant correlation between theDFA and the PTA and PCL injury (P > 0.05). A decreased PTS significantly alters the biomechanical environment of the knee during flexion. Under normal conditions, the femoral condyles tend to roll posteriorly on the tibial plateau during knee flexion. However, a reduced PTS restricts this physiological posterior rolling. To maintain the knee’s instantaneous center of rotation, the femoral condyles exert an anteriorly directed thrust on the tibia during flexion. This biomechanical alteration directly leads to a significant increase in tension borne by the PCL(Fig. 6). Consequently, during PCL reconstruction surgery, precise adjustment and restoration of an appropriate PTS is considered an important biomechanical strategy to potentially reduce the risk of graft re-rupture.
Fig. 6.
Demonstrates that a reduced PTS alters the knee’s biomechanics during flexion. Under normal conditions, the femoral condyles tend to roll posteriorly on the tibial plateau during knee flexion. However, a decreased PTS restricts this posterior rolling movement. To maintain the knee’s instantaneous center of rotation, the femoral condyles exert an anteriorly directed thrust on the tibia during flexion. This anterior thrust significantly increases the tension borne by the PCL
This study has several limitations. First, the retrospective design rather than a prospective approach, coupled with a relatively small sample size and a mild imbalance in sample size between the two groups, may introduce bias into the statistical analyses and affect the robustness of the findings. Second, the reliability and validity of the measurement methods were not assessed, which could introduce some error in the calibration of anatomical parameters and the interpretation of the results. Furthermore, as a single-center study, the relatively concentrated source of subjects may limit the generalizability of the conclusions. Future research should employ large-scale, multicenter prospective designs and strengthen the standardization and validation of methodologies to further confirm the reliability of the current conclusions.
Conclusion
Our study demonstrated that a decreased PTS and a narrowed femoral intercondylar notch angle are associated with an increased risk of primary PCL rupture. Individuals with a PTS of less than 6.5° and a femoral intercondylar notch angle of less than 49.5° are particularly susceptible to PCL rupture. Therefore, during PCL reconstruction surgery, precise adjustment and restoration of an appropriate PTS is considered an important biomechanical strategy to potentially reduce the risk of graft re-rupture.
Supplementary Information
Acknowledgements
We would like to thank all the participants, our school, and the hospital.
Abbreviations
- PCL
Posterior cruciate ligament
- ACL
Anterior cruciate ligament
- MCL
Medial collateral ligament
- LCL
Lateral collateral ligament
- PTSA
Posterior Tibial Slope Angle
- LPTA
Lateral Proximal Tibial Angle
- LDFA
Lateral Distal Femoral Angle
- NWI
Intercondylar notch width index
- BMI
Body Mass Index
Authors’ contributions
Jun Ma and Donger Hai designed the study. Donger Hai, Jing Song, Xiaoyu Zhang, Fei Tian and Xilong Ma conducted the investigation. Donger Hai wrote the manuscript. Donger Hai and Jing Song conducted the analysis. Jun Ma revised the manuscript. All authors contributed to the article and approved the submitted version.
Funding
The Internet Plus Health Care Project (Grant No. 2023CJE09036).
This study was supported by the Sports Prescription Project (Grant No. 2023BEG02061).
Data availability
The data and materials are available.All data generated or analysed during this study are included in this published article [and its supplementary information files].
Declarations
Ethics approval and consent to participate
The study was carried out in accordance with the guidelines of the Declaration of Helsinki and Good Clinical Practice. The study protocol was approved by the Medical Ethics Committee of People’s Hospital of Ningxia Hui Autonomous Region (approval number: 2025-LL-021). Written informed consent was taken from all participants.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Data Availability Statement
The data and materials are available.All data generated or analysed during this study are included in this published article [and its supplementary information files].